1. Field of the Invention
The present invention relates to an expanding card mechanism, and more particularly, to the expanding card mechanism in combining an upper case with a lower case.
2. The Prior Arts
Electronic products often need different expanding card mechanisms to increase application areas such as various memory cards, USB cards, and wireless network cards. The expanding card mechanisms in these different application areas need a solid case to protect a circuit board. The solid case is generally made of stainless steel or magnesium alloy. Furthermore, an insulated plastic device matches a proper mechanism design in order that the case forms a vigorous combination to attain electrical insulation and protection function.
FIG. 1 and FIG. 2 are perspective views of a plastic frame rack, a joint and a lower case of a conventional expanding card mechanism. The plastic frame rack 10 has positioning concave slots 11a, 11b, 11c, 11d, 11e, 11f and 11g for matching a lower case 20 of C shaped positioning hooks 21a, 21b, 21c, 21d, 21e, 21f and 21g, such that the corresponding positioning hooks are well locked in the positioning concave slots. In addition, a positioning pinhole 17 of the plastic frame rack 10 matches a positioning convex block 27 of the lower case 20, a positioning hole 15 of the plastic frame rack 10 matches a positioning convex rim 25 of the lower case 20, and the plastic frame rack 10 is tightly combined with the lower case 20. The plastic frame rack 10 has two joint card slots 16a and 16b for matching two joint convex blocks 36a and 36b of the interface joint 30 to assemble the interface joint 30 in the plastic frame rack 10.
FIG. 3 is a perspective view of an upper case of a conventional expanding card mechanism. The upper case 40 has two positioning convex blocks 43a and 43b for matching two positioning concave slots 13a and 13b of the plastic frame rack 10, and two positioning convex chips 48a and 48b of the upper case 40 match two positioning concave slots 18a and 18b of the plastic frame rack 10. A circuit board (not shown) is assembled between the upper case 40 and the lower case 20. The upper case 40 has three guiding slots 49a, 49b, and 49c for matching the corresponding outer sides of the lower case 20 such that the upper case 40 is vigorously combined with the lower case 20.
FIG. 4 is a perspective view of a conventional expanding card mechanism. The expanding card mechanism 50 includes the interface joint 30, the upper case 40, and the lower case 20 (not shown). The lower case 20 is under the upper case 40. The expanding card mechanism 50 provides the interface joint 30 for electrical connection, and its solid case provides the protection function. One of the drawbacks of the conventional expanding card mechanism is that the plastic frame rack and the lower case are vertically assembled by combining the positioning concave slots with the positioning convex blocks. However, the assembly force provided only by combining the positioning concave slots with the positioning convex blocks is weak for the plastic frame rack and the lower case. Additionally, the vertical insertion assembly results in the thickness of the plastic frame rack being larger than that of the lower case, and therefore the location level of the plastic frame rack is higher than that of the lower case. This defect may make the plastic frame rack depart from the lower case due to the outer mechanical force in the following step of assembly manufacture, and even damage the expanding card mechanism.
Another drawback of the conventional expanding card mechanism is that the positioning concave slots of the plastic frame rack may depart from the positioning hooks of the lower case because of externally squeezing in the horizontal direction. Accordingly, the combination force for the plastic frame rack and the lower case is weak on the sides, the yield rate of the expanding card mechanism is affected, and similarly, the endurance and reliability of the final product are also degraded.
Therefore, it is greatly desired to provide a strong solid expanding card mechanism to deal with the externally squeezing force during the assembly procedure in order to improve the yield rate and reliability of the expanding card mechanism.